1. Field of the Invention
The present invention relates generally to coverings for architectural openings and more particularly to a skew adjustment device positioned within the head rail of the covering to maintain a uniform rollup of covering fabric onto a roller disposed within the head rail.
2. Description of the Relevant Art
Coverings for architectural openings have assumed different forms over many years. Early forms of coverings simply consisted of fabric draped across all or some portion of an architectural opening such as a door, archway, window or the like.
Retractable coverings have also been a popular product wherein the covering is either suspended vertically and retracted to one or both sides of the architectural opening or rolled up or down about a roller at the top or bottom of the opening. The latter category of retractable coverings include a flexible fabric or fabric like material that is connected to a roller and can be retracted about the roller in a retracted condition of the covering or extended from the roller across the architectural opening in an extended condition.
One problem with retractable coverings that include a flexible material that is wound onto or unwound from a roller resides in the material skewing as it is wound onto the roller or unwound from the roller. When the material skews, it translates horizontally along the longitudinal axis of the roller as it is raised and wraps around the roller in a spiral fashion sometimes referred to as barber poling. As a result, the bottom rail along the bottom edge of the material is not desirably horizontally disposed during operation of the covering. Skewing of the material can be caused by various features of the covering including the roller not being horizontally mounted, the fabric not being fixed to the roller horizontally, or the fabric being asymmetrically configured, but regardless of the cause of the skew, it is aesthetically undesirable and can cause the fabric to engage the housing for the roller where it can fray. Accordingly, attempts have been made to correct skew.
Typically, the skew is corrected with a ballast bar or bars slidably positioned in the bottom rail of the covering so that the ballast bar or bars can be releasably fixed at any desired location along the horizontal length of the bottom rail. This of course shifts the center of gravity of the bottom rail which counters the bias in the covering material so that the bottom rail remains horizontal as desired for operation and aesthetics.
While ballast bars in the bottom rail are typically concealed within the bottom of the bottom rail, under certain circumstances, they can become visible and accordingly alternative anti-skew systems are continually being investigated.
It is to provide an alternative skew adjustment system that the present invention has been developed.